Wheel bearings sometimes use seal assemblies that incorporate a pair of metal casings, one installed to each bearing race. Typically, an elastomer seal comprising two or more seal lips is molded to one casing, and the seal lips ride on surfaces of the other casing. An example of such a seal may be seen in U.S. Pat. No. 4,497,495 to Christiansen, assigned to the assignee of the subject invention. The sealing effectiveness depends on the the degree to which the lips are deflected out of their free state as they ride on the seal surfaces, as well as the orientation they have with the seal surfaces. There will be an ideal or nominal installation position of the seal casing relative to the other casing, at which the seal lips will be deflected to just the desired degree. However, tolerance variations, which result from stamping the casings, molding the seal, and from imperfections in the installation process, prevent the seal casings from always having the desired relative spacing and orientation. In order for the seal lips to be deflected enough when the seal casings are farther apart, extra seal lip deflection, and a change in seal lip orientation, has to be tolerated when the casings are closer. Sealing friction and wear are higher than desired when the seal lips are over deflected.